Conventionally, a control system with an ECU including a nonvolatile memory that stores failure information is known (for example, refer to Patent Literature 1). In this control system, self-diagnosis of system components is performed by the BIT function of the ECU. When an abnormality is detected in the system components as a result of the self-diagnosis, the failure information is stored in the nonvolatile memory.
Further, a plant operation information recording method is known which records plant operation information before and after an abnormality of a plant occurs when the abnormality occurs during a normal operation of the plant (for example, refer to Patent Literature 2).